A Low-Power PEDOT: PSS/EB-PANI for CO2 Sensing Material Integrated With a Self-Powered Sensing Platform

The Internet of Things (IoT) has inspired key directions for next-generation sensor development. These directions include low power and good selectivity to promote IoT applications. To address this point, in this work, we developed a low-power and room-temperature-operation CO2 sensing material with high selectivity to humidity. The sensing material was developed based on (emeraldine based polyaniline)/(poly(3,4-ethylenedioxythiophene)-poly (styrene sulfonate) composites, i.e. EB-PANI/PEDOT:PSS. Its selectivity to humidity was experimentally verified from 55% RH to 85% RH. In brief, the sharing of PSS between PEDOT and EB-PANI improved the conductivity and CO2 sensing characteristics of the composite sensing material. At the same time, the opposite humidity-sensing responses of PEDOT and PANI counteracted to each other and resulted in a high selectivity to humidity. In this work, the optimal weight ratio of an EB-PANI/PEDOT:PSS sensing film for CO2 monitoring and immunity to humidity interference was also discussed. To demonstrate the feasibility of integrating the developed sensing material into an IoT system, a self-sustained system-on-chip (SoC) platform for expiration CO2 detection was implemented and experimentally operated with indoor illuminance conditions.